1. Field of the Invention
The present invention relates generally to a mechanism for generating vibration horizontally or vertically and, in particular but not exclusively, to a vibration generating mechanism for generating vibration energy in either the horizontal direction or the vertical direction by making use of repulsive forces of a plurality of permanent magnets.
2. Description of Related Art
An exciter or vibration generator has been used to artificially generate vibration to investigate vibration characteristics of a structure. Exciters of an electromotive type and those employing an unbalanced mass or a cam are known.
An exciter employing a link mechanism such as, for example, a crank is, however, required to have a relatively large drive motor because a load is directly applied to the drive motor, while an exciter of the electromotive type cannot cope with low frequencies.
Also, because conventional exciters are generally large in size, not only a relatively large space but time-consuming installation work are required. Further, the conventional exciters generate a large amount of heat and, hence, require forced air cooling by a fan or the like, which in turn causes a problem in that noise evaluation cannot be achieved.
In addition, because the conventional exciters are generally of a complicated structure and are, hence, heavy and costly, light and inexpensive ones have been desired.